Magnetic reader with read head biased against document by resilient deflection of circuit board

ABSTRACT

A document reader, such as a hand-fed check reader is described herein. The reader includes a transducer elastically supported relative to a circuit board. Components and circuitry to manipulate signals produced by (read head transducer), or applied to (write head transducer), the transducers are supported by the circuit board. The transducer is supported by a spring member fabricated from the circuit board material, where the board is mounted relative to a document path of travel such that the transducer is biased against the document. A drive wheel and mechanism is provided to move the document along the path and bias the document against the transducer in the vicinity of magnetic information on the document.

CROSS-REFERENCE TO RELATED APPLICATIONS

The following application is related to U.S. patent application Ser. No.08/040,629, entitled "Apparatus for Reading Magnetic Information from aDocument Subsequent to Aligning the Dipoles of the Information," filedApr. 1, 1993 by Abel, et al.

FIELD OF THE INVENTION

This invention generally relates to the reading of magnetically codedinformation from a document. More particularly, the present inventionrelates to a document reader which can be efficiently manufactured andpermit efficient reading of hand-fed documents such as checks submittedat a point-of-sale.

BACKGROUND OF THE INVENTION

The technology of reading information which is magnetically encoded ondocuments has been developed for use in a number of areas, includingbanking. Machines have been developed for use in the banking industry toread magnetically encoded information from checks, such as the bank fromwhich the check was drawn and the account number ("ON US" field). Thesemachines are designed for high speed check reading (e.g. 5000 to 10,000checks per hour) with very high reading accuracies. However, thesemachines are relatively large and very expensive. Accordingly, theirsize and cost limit their range of application. For example, there ispresently a need and desire at point-of-sale (POS) locations in retailstores to read magnetically encoded information from checks withouthaving to key the information into a data entry terminal.

The need for POS check reader is only partly fulfilled. For example,Fargo Electronics makes such a drive, sold under the name the"CheckReader". Another example is the Onyx check reader produced byVeriFone. Devices of this type are typically sized and pricedappropriately for use at POSs. However, many check readers which areusable for check reading at POSs suffer a number of problems, includingcheck reading inaccuracy, difficult or awkward hand presentation of acheck to the reader, and electromagnetic sensitivity. Additionally,these readers are only designed to read one type of magnetically encodedcharacter type.

Check reading inaccuracy can be caused by magnetic interference, andresults either in a misread check or an error signal. The problem ofelectromagnetic sensitivity is usually caused by the requirement that acheck reader be located close to a cash register, scale or UPC scanner.This sensitivity results in reduced reading accuracy or inoperability.

Referring to the inability of typical POS check readers to readdifferent types of magnetically encoded characters, this problem isusually the result of signal filtering techniques used when readingmagnetically encoded characters. For example, a check reader configuredto read E-13B character types (used as a standard in the U.S. and partsof Europe) will typically be unable to read CMC-7 character types (usedas a standard in France and parts of South America).

Another cause of reading inaccuracy is the manner in which themagnetically encoded information is applied or incorporated into thedocument (check). In particular, magnetically encoded information isusually applied to documents with relatively inexpensive desktopprinters. These devices can apply magnetic material (toner) in such away that the resulting magnetic configuration will be anisotropic,normal to the plane of the document. This type of configuration isproblematic in that it can not be properly read if not correctlymagnetized.

The configuration of E-13B character type and poor ergonomic design canresult in difficult and awkward hand presentation of checks to POS checkreaders. More specifically, E-13B style was designed to be read from theright to left. Accordingly, the read head of a check reader in relationto the feed arrangement should be positioned so that the person feedingthe check to the reader is capable of accomplishing this task with anatural motion and the least amount of manipulation of the check,regardless of whether the person is right or left-handed. The ability ofa person to efficiently present checks to the check reader is importantin most POS situations due to the relatively high volume of customerservice required.

Accordingly, it would be advantageous to provide a POS-type check ordocument reader with improved accuracy, the ability to read more thanone character type, and have a configuration designed to improve theease at which a check can be presented to the reader. Additionally,these improvements should be provided without substantially increasingthe cost of the check reader.

SUMMARY OF THE INVENTION

The present invention provides for a device for interacting with themagnetic information of moving surfaces. The moving surface may be of acheck having information such as characters printed thereon withmagnetic ink. The device includes a circuit board which supports atransducer, and an amplifier circuit coupled to the transducer. Forapplications where the transducer is a read head which interacts withthe magnetic information by reading the information, the amplifiercircuit amplifies signals produced by the transducer. Where thetransducer is a write head which configures magnetic information on thedocument, the amplifier amplifies signals applied to the transducer. Thecircuit board includes a support portion suspended relative to thecircuit board by a support member. The support portion and member arefabricated from the material of the circuit board, such that the circuitboard may be positioned to bias the transducer against a movingdocument.

The present invention may be embodied in devices such as check readers.Such check readers may be of the hand fed type having check housings,support surfaces and drive mechanisms configured to permit efficienthand-fed check reading.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will hereinafter be described with reference to theaccompanying drawings, wherein like reference numerals denote likeelements, and:

FIG. 1 is a perspective view illustrating a check reader;

FIG. 2 is a side elevation view illustrating the check reader;

FIG. 3 is an end elevation view illustrating the check reader;

FIG. 4 is a top plan view illustrating the check reader;

FIG. 5 is an end elevation view illustrating the check reader;

FIG. 6 is a side elevation view, similar to FIG. 2, illustrating theopposite side of the check reader;

FIG. 7 is a bottom plan illustrating the check reader;

FIG. 8 is an exploded perspective view illustrating the check readerread head, document mechanism drive, and printed circuit board andhousing;

FIG. 9 is a sectional view taken along line 9--9 in FIG. 5;

FIG. 10 is a sectional view taken along line 10--10 in FIG. 9;

FIG. 11 is a sectional view taken along line 11--11 in FIG. 9;

FIG. 12 is a sectional view taken along line 12--12 in FIG. 9;

FIG. 13 is a top plan view of the printed circuit board shown in FIG. 8;

FIG. 14 is a representation of a check to be read;

FIG. 15 is a block diagram of the check reader circuitry;

FIG. 16A is a schematic diagram for a read head amplifier and ananalog-to-digital converter used in a check reader of the presentinvention;

FIG. 16B is a schematic diagram for an audible transducer circuit;

FIG. 16C is a circuit diagram for a form sensor circuit;

FIG. 17 is a schematic diagram for a stepping motor control;

FIG. 18A is a schematic diagram of a power supply;

FIG. 18B is a schematic diagram of a battery backup circuit;

FIG. 19 is a schematic diagram of a processor circuit;

FIG. 20 is a schematic diagram of an interface selection circuit;

FIG. 21 is a schematic diagram of a display circuit; and

FIG. 22 is a block diagram of the programmed processor circuit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1-8, the housing of a check reader 10 generallyincludes a housing base 12, components cover 14, a display and sensorwindow 16, and a bottom cover plate 18.

Housing base 12 includes a check support surface 20 having a flatportion 22 extending into a curved surface 24. Surface 24 includes asubstantially rectangular depression 26 designed to include display andsensor window 16. Surface 22 and the top surface of window 16 lie insubstantially the same plane to provide a planar surface for slidablysupporting a document such as a check 158 (FIG. 14). Depression 26 isadjacent to a document guide rail 28.

In the present embodiment, rail 28 is molded integrally with base 12,has a substantially rectangular cross-section, and extends upwardly fromthe planar surface formed by the top surface of window 16 and surface22. Rail 28 is generally straight along surface 22, and is configured tofollow surface 24. This configuration of rail 28 provides a surface 30which is substantially perpendicular to the plane within which surface22 and the surface of window 16 lie, and a surface 31 which issubstantially perpendicular to surface 24. Rail 28 includes alongitudinal axis 32 which is parallel to surface 22, and parallel tothe direction of travel of a check which is slid along the surface 22and the surface of window 16, as generally indicated by arrow 34.

Housing base 12 also includes a display port 36, a sensor port 38 and amagnet support pocket 76. Both of these ports are formed withinrectangular depression 26 and are covered by window 16, where pocket 76is molded into depression 26 between rail 28 and port 38. Display orsensor devices disposed within ports 36 and 38. At the interface betweenflat surface 22 and curved surface 24, a read head opening (port) 40,which may be rectangular, is located adjacent to guide rail 28.Extending downwardly from surfaces 22 and 24 are side walls 42, 44, 46and 48. Side walls 42, 44, 46 and 48 are generally perpendicular tosurface 22 and include formations such as screw pedestals (not shown)which allow bottom cover plate 18 to be fastened to the bottom of base12, as generally shown in FIG. 10. Side wall 46 also includes twoopenings 72 and 74 configured to provide access to multi-pin connectors(see FIG. 3).

Housing base 12 also includes a document drive mechanism support 50which extends outwardly from side wall 48. Support 50 includes a pair ofside support walls 52 and 54 extending perpendicular to, and outwardlyfrom, side wall 48. Walls 52 and 54 terminate at a support wall 56 whichis substantially parallel to side wall 48 (see FIG. 9). A motor andbearing support platform 58 extends between walls 52, 54 and 56 and liesbelow flat surface 22. Platform 58 lies in a plane substantiallyparallel to the plane within which surface 22 lies.

A first bearing support 60 extends upwardly from the motor and bearingsupport platform 58 (see FIG. 11). As best shown in FIG. 8, support 60includes a pedestal 62 and a pair of flexible bearing grips 64 forengaging a bearing, as discussed below. A worm gear bearing support 66extends upwardly from platform 58 and from the top of wall 56. Anopening 68 in side wall 56 supports a shaft bearing 70, as discussedfurther below.

By way of example, housing base 12 may be molded from a thermoplasticmaterial, such as ABS, T-grade, using an injection molding process. Byway of further example, display and sensor window 16 may be fabricatedfrom a substantially clear plastic material, where a coloring agent isprinted on the lower surface of the material to make its surface colorappear substantially the same as flat surface 22. Window 16 may also befabricated to include an adhesive lower surface. The adhesive fastenswindow 16 in rectangular depression 26.

Components cover 14 has a generally box-like configuration including atop wall 78 substantially parallel to surface 22, side walls 80 and 82substantially parallel to support walls 52 and 54, and end walls 84 and86 substantially parallel to support wall 56. Walls 78, 80, 82, 84 and86 are integrally molded as one cover 14, where walls 80, 82 and 86intersect wall 78 and each other at rounded corners. Wall 84 intersectswalls 78 and 80 at substantially right angle corners. The sizing ofcover 14 allows walls 80, 82 and 86 to contact the outer surfaces ofwalls 52, 56 and 54, respectively, when cover 14 is mounted on base 12.Cover 14 is held onto base 12 by cooperation of tabs and grooves inwalls 52, 80, 54 and 82 (not shown).

Walls 78 and 84 extend over surfaces 22 and 24, respectively, and wall78 supports wall 84 over surface 24 and a portion of surface 22. Surface24 has a radius of approximately 1 inch, where wall 84 includes a loweredge 88 which is substantially parallel to surfaces 22 and 24 along theportions of these surfaces over which it extends. This configuration ofwalls 78, 80 and 84 prevents access to the components housed under cover14 while also allowing the document to be passed between walls 78, 80and 84 and surfaces 22 and 24.

Referring to FIGS. 8-12, a document drive mechanism 90 includes adocument drive wheel 92, a drive wheel support shaft 94, a helical gear96, a worm drive gear 98, and a two pole stepping motor 100. In thepresently preferred embodiment, wheel 92, shaft 94 and gear 96 aremolded as a single piece component, with the peripheral surface of wheel92 being molded from a material different from the material making upthe hub of wheel 92, shaft 94 and gear 96. More specifically, theperipheral surface of wheel 92 is fabricated from a material havingproperties sufficient for providing adequate frictional engagementbetween wheel 92 and the surface of a document. By way of example, thesurface of wheel 92 may be fabricated from a material such aspolyurethane, neoprene or rubber, and the wheel 92 hub, shaft 94 andgear 96 may be fabricated from a material such as acetal.

Worm drive gear 98 is fastened directly to the shaft of motor 100 and isrotatably supported within document drive mechanism support 50. The axisof gear 98 is perpendicular to the axis of support shaft 94. Inparticular, worm drive gear 96 is rotatably supported by the bearings ofmotor 100 and a cap bearing 102 supported by worm gear bearing support66. Bearing 102 rotatably supports gear 96 at its top end, and is snapfit into a bearing retention slot 104 in support 66. Motor 100 isfastened to the bottom of motor and bearing support platform 58 at itsflange 112 by a pair of screws 114 which are self-threaded into platform58.

Document drive wheel 92 and worm gear 96 are both rotatably supportedwith shaft 94 relative to worm drive gear 98 and surface 22 by capbearing 70 and a half journal bearing 108. Cap bearing 70 is supportedwithin opening 68 and rotatably supports the corresponding end of shaft94. Journal bearing 108 is a half journal bearing in that it onlyprovides a bearing surface over the top surface of shaft 96. Bearing 108rotatably engages shaft 94 between wheel 92 and gear 96. Shaft 94 isheld into rotational engagement with bearing 98 by the resultant upwardforce caused by the interaction of worm gear 98 and drive gear 96, andthe upward force applied to drive wheel 92 by a magnetic transducer 110(discussed below).

In general, the components of document drive mechanism 90 are configuredto reduce the number of components in reader 10. This configuration alsoreduces the number of steps required to assemble drive mechanism 90within document drive mechanism support 50. More specifically, referringto FIG. 8, mechanism 90 is assembled into support 50 as follows:

1. Worm drive gear 98, motor 100 and cap bearing 102 are locatedrelative to platform 58 by passing gear 98 and 102 through an opening116 in platform 58;

2. Bearing 102 is engaged with retention slot 104, and motor 100 isfastened to the bottom of platform 58 by screws 114;

3. Support shaft 94, cap bearing 70, gear 96 and wheel 92 are locatedrelative to the platform 58, and cap bearing 70 is engaged with the freeend of shaft 94 and is engaged with opening 68 in wall 56; and

4. Half journal bearing 108 is placed over shaft 94 between gear 96 andwheel 92, and forced downward until flexible bearing grips 64 engage apair of bearing shoulders 118 to hold bearing 108 between pedestal 62and grips 64.

To provide positional stability for journal bearing 108, a pair of pins(not shown) may be provided in the top surface of pedestal 62, where thebottoms of shoulders 118 include mating opening holes (not shown).

By way of example, bearings 70, 102 and 108 may be fabricated using amolding process and a material such as polyester. Additionally, the gearratio provided by the combination of drive gear 96 and worm gear 98 maybe in the range of 12-to-1. However, while the gear arrangement shownprovides an adequate gear reduction in a relatively small space, it maybe preferable to use other drive arrangements (e.g. direct drive, spurgear drive, chain drive, belt drive), depending upon the application, asthis configuration is only about 55% efficient.

Referring to FIGS. 8-13, a circuit board structure 120 includescircuitry having various discrete components and connections asdescribed in detail below in reference to FIGS. 15-21. The mechanicalsupport for the circuitry and components thereof is a planar circuitboard 122 of the type manufactured from a material such as FR-4. (Forpurposes of clarity, only some of the components are shown on board 122in FIG. 13.) The circuit connections of circuit board 122 may reside inone or more planes within the circuit board to connect the components ofthe circuitry. Structure 120 may be fastened within housing base 12 tothree screw pedestals 126 by three self-threading screws 128 extendingthrough openings 124 in board 122. Structure 120 is fastened within base12 such that circuit board 120 lies in a plane which is generallyparallel to planar surface 22 (see FIGS. 10-12).

In addition to supporting the components of the circuitry for checkreader 10, circuit board 22 supports magnetic transducer 110, an LED130, a photo transistor 132, and an LED display 134. When transducer 110is mounted upon circuit board 122, transducer 110 extends throughtransducer head opening 40. More specifically, opening 40 is configuredto include four side walls 136 extending downwardly from surfaces 22 and24 such that they form a rectangular channel having a central axis 138which is perpendicular to, and intersects, the longitudinal axis ofdrive wheel support shaft 94.

LED 130 and photo transistor 132 are mounted upon circuit board 22relative to sensor port 38 such that the edge of a document passing overport 38 can be sensed. The edge is sensed as the result of theapplication of light through port 38 by LED 130 and the response ofphoto transistor 132 to a change in the reflected light as a result ofthe passage of an edge of the document past port 38. LED display 134 ismounted to circuit board 122, and the information on display 132 may beread through port 38.

Referring back to FIG. 10, LED 130 and transistor 132 are surrounded bycylindrical walls 131 and 133, respectively. Walls 131 and 133 increasethe accuracy with which transistor 132 senses the passage of an edge, byreducing the amount of light which LED 130 directly applies totransistor 132. Depending upon the characteristics of LED 130 andtransistor 132, the orientation and lens configurations could be variedto improve the accuracy and reliability of edge sensing for a particularapplication.

Referring again to magnetic transducer 110, this transducer is suspendedrelative to circuit board 122, and allowed to move relative to circuitboard 122 (e.g., vertically along an axis substantially perpendicular tothe surface of board 122), by being mounted upon a spring member 140fabricated from the material of circuit board 122. Spring member 140permits head 110 to be elastically deflected relative to circuit board122. When circuit board structure 120 is mounted within base 12, a topsurface 142 of transducer 110 is biased with a predetermined force(e.g., 4-16 ounces) against the bottom of document drive wheel 92.Accordingly, when a document is fed into check reader 10, it is forcedagainst drive wheel 92 by top surface 142 to provide an appropriateforce normal to the surface of wheel 92 to permit wheel 92 to drive thedocument along transducer 110. In other words, head 110 is resilientlymounted with respect to board 122.

As will be recognized, the configuration of spring member 140 could takea number of forms, such as the one of the present embodiment, whichincludes a substantially rectangular head support portion 144, a firstL-shaped leg 146, and a second L-shaped leg 148. As shown in FIG. 13,spring member 140 is bounded by first and second grooves 150 and 152,which may be appropriately machined or cut into circuit board 122. Aspring member 140 fabricated from the material of, and integrally with,circuit board 122, provides a way to spring mount transducer head 110relative to base 12 and wheel 92 without the need for additional springsand various other support structures which are costly in that they mustbe manufactured and assembled into check reader 10. It has been foundthat the fabrication of a spring such as member 140 from the circuitboard material provides a spring which has properties which are as, ormore, satisfactory than a conventional metal based spring.

The provision of a spring member 140 fabricated from the material ofcircuit board 122 allows the electrical connections from transducer 112to the circuitry of circuit board 120 to pass along L-shaped legs 146and 148. This eliminates the need for separate leads between transducer120 and the circuitry of board 120 to which the signals from transducer110 are applied. However, there may be applications where, for variousreasons, it may be desirable to couple transducer 110 with theassociated circuitry by leads which are not fabricated upon circuitboard 122.

Certain problems may be encountered in the operation of check reader 10.Non-circular and non-concentric wheels 92 is one of these problems. Oneof the problems caused by non-circular and non-concentric wheels 92 isthat transducer 110 may bounce against the document being moved by wheel92. To dampen this bouncing, a dampening material such as a felt orrubber tab 154, or other suitable material may be fastened (e.g. glued)within panel 136.

In reference to magnet support pocket 76 located in depression 26, anassociated support pocket 77 is located within components cover 14 atthe bottom of wall 80, directly over support pocket 76. Magnet supportpockets 76 and 77 both include magnets 79, 81 for appropriately aligningthe dipoles of magnetic information included on or in the documentpassed through reader 12. Magnets 79, 81 may be permanent magnets orelectromagnets, and have their poles aligned along an axis 156 which issubstantially perpendicular to surface 22. This arrangement of magnets79, 81 orients the magnetic dipoles of magnetic information (characters)on the document in one direction to provide a condition such assaturation. The location of magnet support pockets 76 and 77 providesmagnets 79, 81 on opposite sides of the document transport path 34 alongthe surface 22. The magnets should be configured to provide amagnetizing force which is greater than the coercive force of themagnetic dipoles on the documents, and the magnetic poles of the magnetsshould be facing each other. Thus, for example, both south poles couldbe located adjacent to each other or both north poles could be locatedadjacent to each other. Further information relating to theconfiguration of the magnets and optimization of their location may befound in U.S. Pat. No. 4,107,653, issued on Aug. 15, 1978 to KarlisKruklitis.

For certain applications it may be useful to use electromagnetsactivated by direct current for magnets 79, 81. Magnets 79, 81 couldthen be selectively energized to leave the magnet off when not needed,or selectively polarized as required. In another alternative, magnet 81could be eliminated. This arrangement would align the dipoles ofmagnetic information on the document as the information passed over onepole of the magnet. As still another alternative, it may be desirable touse a combination of a permanent magnet and an electromagnet.

The details of the operation of the components and circuitry of circuitboard structure 120 will be discussed below; however, the overalloperation of check reader 10 will be discussed now in reference to check158 illustrated in FIG. 14. Before discussing the operation of checkreader 12, the configuration of check 158 will be described.

The location of information on checks is generally specified in theAmerican National Standard Bank Check Specifications for Magnetic InkCharacter Recognition (MICR). Under these specifications, the right edgeof a check, when its face is viewed, is used as a reference edgereferred to as 160. The specification provides for a MICR character setreferred to as E-13B characters used in printing or encoding informationon documents which enables them to be processed by standard sortingmachines. Standard fields on check 158 are the EPC field 162, therouting field 164, the "ON US" field 166, and the amount field 168. Theinformation in these fields is printed in magnetic ink. A typicalpersonal check is 6 inches long and about 21/2 inches wide. The centerof the EPC field 162 is 5.75 inches from the right edge, the right edgeof routing field 164 is 4.250 inches from the right edge, the right edgeof "ON US" field 166 is 1.875 inches from the right edge 160, and theright edge of amount field 168 is 0.3125±0.0625 inches from right edge160.

In light of the location and orientation of the MICR information oncheck 158, the configuration of check reader 10 is important from anergonomic standpoint in that it must be set up to permit the user toeasily direct a check into reader 10. More specifically, in addition toscanning the information in fields 162, 164, 166 and 168, thisinformation may be entered manually via a 10-key numerical keypad.Accordingly, if the configuration of a check reader makes it difficultto easily and quickly direct a check therethrough, a skilled keypadoperator may be able to input the information faster by using a keypadthan by using the check reader. Since the overall purpose of a checkreader is to increase the speed of data entry, the structural design ofthe check reader is important.

The structural design of check reader 10 which, while having manyfeatures which are ornamental, has certain features which allow a checkto be efficiently directed through reader 10. More specifically, thelocation of rail 28 relative to surfaces 22 and 24, the location of head110, and location of document drive mechanism 90 permit efficientface-down feeding of checks by either a left or right-handed person whenhanded a check face up for viewing. For personal checks which are 6inches long and approximately 2 1/2 inches wide, flat surface 22 ispreferably about 3 inches wide and 5 inches long, where 4 inches ofsurface 22 is provided in front of side wall 80. By providing thissurface size along with document guide rail 28, the user can efficientlytake check 158, press it face down against rail 28 on surface 22, anddirect the check toward magnetic transducer 110 and document drive wheel92.

In operation, when a document such as check 158 is inserted into checkreader 10, with the fields positioned face down and adjacent to guiderail 28, the left edge 170 of check 158 is sensed by photo transistor132 which causes the control circuit (discussed below) of check reader10 to run motor 100. Motor 100 and gears 96, 98 cause document drivewheel 92 to rotate in a clockwise direction and pull check 158 alongsurfaces 22 and 24. 30 When check 158 moves along surfaces 22 and 24,the MICR information in fields 162, 164, 166 and 168 pass over magnetictransducer 110. As the MICR information passes over magnetic transducer110, this information is sequentially stored by the control circuit.When photo transistor 132 provides a second signal to the controlcircuit which is representative of the passing of edge 160, the controlcircuit runs motor 100 for a predetermined number of revolutions orportions of revolutions required to drive the check from engagementbetween wheel 92 and transducer 110. This allows the user to remove thecheck from the top edge 172 of surface 24 without tearing off a cornerof the check, which may be caught between wheel 92 and transducer 110.

The control circuit of check reader 10 will now be described inreferences to FIGS. 15-21. The components of check reader 10 with theexception of motor 100 and document drive mechanism 90 are mounted uponPC board 122. As discussed above, this configuration greatly reduces thenumber of structural members within reader 10 by using PC board 122 notonly as a circuit board, but also as a structural member. As can readilybe appreciated, this use of PC board 122 substantially reduces materialand assembly costs.

Referring to FIG. 15, the circuitry of check reader 10 generallyincludes a magnetic transducer 110, an amplifier and prefilter circuit1502, an analog-to-digital converter (A/D) 1504, an audible transducercircuit 1506, a form sensor circuit 1508, a motor drive circuit 1510, apower supply 1512, a battery backup circuit 1513, a processor circuit1514, a display circuit 1516, and an interface selection circuit 1518.In general, the circuitry allows the check reader to read magneticallyencoded information (MICR characters) from a document (check 158),convert the information into an electrical signal, display check readerstatus information, display information from another device coupled tothe check reader, display information from check 158, selectivelyinterface with other devices using various hardware interface,controllably drive motor 100, and provide power to check reader 10. Morespecifically, a microprocessor 1902 of circuit 1514 (FIG. 17) appliessignals to the circuitry of the check reader as shown in the followingtable A.

                  TABLE A                                                         ______________________________________                                        SIGNAL   PORT, LINE   DESCRIPTION                                             ______________________________________                                        Beep     3, 5         A pulse train applied by                                                      processor 1702 to resistor                                                    1680 of circuit 1506.                                   Form     3, 2         A pulse applied from                                                          invertor 1690 of circuit                                                      1508 to processor 1702.                                 Sample   3, 6         A clock signal applied by                                                     processor 1702 to invertor                                                    1664 of A/D 1504.                                       Data     3, 1         A pulse of varying duration                                                   applied from terminal 1642                                                    of A/D 1504 to processor                                                      1702.                                                   M0       2, 0         Motor phase 0 and display                                                     data.                                                   M1       2, 1         Motor phase 1 and display                                                     clear data.                                             /ME0     2, 2         Motor drive signals applied                                                   to control chip 1702.                                   /ME1     2, 3         Motor drive signal applied                                                    to control chip 1704.                                   /DCLK    2, 4         Data signals applied to                                                       display latches 2102 and                                                      2104.                                                   MODE0    2, 5         Interface signals applied to                                                  logic circuit 2022.                                     MODE1    2, 6         Interface signals applied to                                                  logic circuit 2022.                                     /RD      3, 0         Data received from                                                            demultiplexer 2016.                                     /HSI     3, 4         Hand-shake data received                                                      from demultiplexer 2020.                                /HSO     3, 5         Hand-shake data applied to                                                    demultiplexer 2020.                                     /TD      3, 7         Data transmitted from                                                         demultiplexer 2016.                                     ______________________________________                                    

Referring to FIG. 16A, magnetic transducer 110 is coupled to amplifierand prefilter circuit 1502. Transducer 110 may be a read or write head,and in the present embodiment, transducer 110 is a magnetic read head.Transducer 110 includes a balanced winding 1600 which is connected in aseries aiding configuration with a center tap 1602 grounded to produce abalanced output. The voltage produced (electrical signal) is asubstantially linear function of the change in density of magneticmaterial passing across transducer 110. Thus, a unique electrical signalis generated for different characters passing over top surface 142 oftransducer 110. This electrical signal is applied, via leads 1604 and1606, to resistors 1608 and 1610 having capacitors 1612 and 1614connected therebetween. This arrangement provides for a 2-pole,Butterworth, low-pass filter having a cut off frequency of about 768 Hz.By way of example only, transducer 110 may be of the type manufacturedby Mag-Head Engr. Corp.

The terminals of capacitors 1612 and 1614 are connected to thenon-inverting inputs of a pair of operational amplifiers 1616 and 1618.Amplifiers 1616 and 1618 include feedback resistors 1620, 1622, and 1624which provide a differential gain of approximately 600-to-1. The outputof amplifiers 1616 and 1618 are coupled to the illustrated arrangementof resistors 1626, 1628, 1630 and 1632, and amplifier 1634. Thisarrangement provides for a unity gain differential amplifier to convertthe differential output of amplifiers 1616 and 1618 to a single endedoutput.

The output of amplifier 1634 is applied to A/D 1504 by an RC networkincluding a resistor 1636 and capacitor 1638 which form a high passfilter having a cut-off frequency of about 2.8 Hz. Microprocessor 1902(FIGURE 19) applies a sample clock signal to a sample terminal 1640 ofA/D 1504. In response to the sample clock signal, A/D 1504 outputs apulse at data terminal 1642 with a time duration in one state which isproportional to the amplitude of the output signal from amplifier 1634.Accordingly, the time duration is a linear representation of the densityof the magnetic material passing across transducer 110 for a givensample (i.e. a series of durations is representative of a particularcharacter). The pulse is applied to and is measured by a timer (e.g.1.84 MHz time base) of microprocessor 1902. By way of example,microprocessor 1902 applies a sample clock signal to terminal 1640 at arate of 7.68 KHz.

Referring more specifically to A/D 1504, this circuit includes anoperational amplifier 1644 and capacitor 1646 which are coupled as shownto form a differencing integrator. A/D 1504 also includes a comparatorcircuit with histeresis including an XOR gate 1648, and resistors 1650and 1652 coupled as shown. This comparator circuit has 50 mv histeresisand a threshold of approximately half the supply voltage (e.g. 2.5 v).The output of XOR gate 1648 is coupled to an XOR gate 1654. A flip-flopcircuit is included in A/D 1504 which includes a resistor 1656, diodes1658, 1660, and XOR gate 1662. Resistor 1656 is coupled between theoutput of gate 1654 and the anode of diode 1658, and the cathode ofdiode 1658 and the anode of diode 1660 are coupled to the inputs of gate1662. A triggering circuit which includes an invertor 1664, a resistor1666, a capacitor 1668, an invertor 1670, and an XOR gate 1672, wherethe output of invertor 1664 is coupled to the input of invertor 1670 byresistor 1666 and ground by capacitor 1668. The outputs of inventors1664 and 1670 are coupled to the inputs of gate 1672.

In general, A/D 1504 operates to maintain a constant upper limit voltageon integrator 1644. Integrator 1644 adds a DC offset (produced by a setof resistors 1674 and 676) to the input signal from amplifier 1634. Theoutput signal is subtracted at 1642 by maintaining a substantiallyconstant voltage on integrator 1644. A pulse train representative of theoutput of amplifier 1634 and the DC offset is output at terminal 1642.The DC offset was chosen at 75% of the supply voltage to provide anoutput range of 0-50%, centered around 25%, of the sampling period at1640 (1/7680*0.25=32.5 uS). These limitations are imposed to avoidinstability which results above 50% of the sampling period.

In operation, a sample clock signal applied at terminal 1640 is modifiedby the triggering circuit to provide modified negative pulses of shortduration, e.g. 200 ns, at the cathode of diode 1660. The negative pulsesreset the flip-flop circuit which causes the output at integrator 1644to rise. When the output at integrator 1644 reaches approximately halfof the supply voltage, the comparator circuit presents a high level tothe anode of diode 1658, whereupon the flip-flop circuit is set. As aresult, the output of gate 1662 produces a negative pulse of nominally25% duration. However, since the output of amplifier 1634 iscontinuously added to the input of integrator 1644, the output dutycycle is modified by an amount proportional to the output signal atamplifier 1634. An invertor 1678 converts the negative pulses at theoutput of gate 1662 to positive pulses which are applied to port 3, line1 of microprocessor 1902.

Audible transducer circuit 1506 (see FIG. 16B) includes a resistor 1680,a capacitor 1682 and a magnetic transducer 1683 (speaker) coupled asshown to produce a sound of predetermined duration. Resistor 1680 iscoupled to port 3, line 5 of microprocessor 1902; thus, a pulse-codemodulated (PCM) signal from microprocessor 1902 is filtered by circuit1506 to produce a particular sound.

Form sensor circuit 1508 (see FIG. 16C) includes LED 130 coupled to thesupply voltage by a resistor 1684, photo transistor 132 coupled to thesupply voltage by a resistor 1688, and an invertor 1690 coupled betweenthe collector of transistor 132 and port 3, line 2 of microprocessor1902. In one embodiment, as discussed above, an axis 1681 of LED 130 isarranged perpendicular to the surface of the document being read, and isdirected at a location just before read head 110. Transistor 132includes a wide angle lens, and is arranged with its axis 1687 parallelto the axis 1681. This arrangement allows LED 130 and transistor 132 tobe directly mounted on PC board 122. (See FIG. 10.) In operation,transistor 132 produces a voltage sufficient to change the state ofinvertor 1690 when the edge of a document passes through its view. Thisresults in a pulse being applied to microprocessor 1902.

Referring to FIG. 17, a stepping motor control circuit 1510 includes afirst stepping motor winding control chip 1702, and a second steppingmotor winding control chip 1704. Chips 1702 and 1704 regulate thecurrent to each winding of stepping motor 100. By way of example, chips1702 and 1704 may be PBL 3717 chips manufactured by Unitrode Corp.,Cherry Semiconductor or Ericson Corp. Two chips 1702 and 1704 are usedsince the present embodiment of motor 100 is a 2-phase bipolar 7.5degree stepping motor. Of course, the type of motor 100 and controlcircuit may be varied depending upon changes in motor technology andavailability.

Each chip 1702 and 1704 is coupled to a dead time circuit including aresistor 1706 and capacitor 1708 coupled in parallel between the timingpin and ground. Each chip 1702 and 1704 is coupled to resistors 1710,1712 and a capacitor 1714. Resistor 1710 is coupled between the currentsense and emitter pins, resistor 1712 couples the emitter pin to groundand capacitor 1714 couples the collector pin to ground. This arrangementprovides low pass filter to remove switching transients, and allows acurrent proportional to the winding current to feed back to the currentsense pin. The ground pins of each chip 1702 and 1704 are grounded, andthe VCC pins are coupled to a 5 volt supply which is filtered bycapacitors 1716. The VMM pins of chips 1702 and 1704 are coupled to a 24volt source and filtered with an EMI filter 1717 and a capacitor 1718 toreduce the application of noise to the voltage source.

The PHASE, I1, I0 and VR pins of chips 1702 and 1704 are connected tothe I/O pins of microprocessor 1902 (e.g. port 2, pins 0-3) by aresistor network, including resistors 1720, 1722, and 1724, which isconnected to the 5 volt source as shown. This arrangement for theconnection provides control from microprocessor 1902 to chips 1702 and1704, which allows the current in stepping motor 100 to be controlled ona half-step basis (3 degree, 45 minute basis) to provide substantiallyequal torque between the armature and rotor of motor 100 throughout arevolution. Since the harmonics of the noise produced by motor 100affect the circuitry of reader 10 and the harmonics of noise increasewith fluctuations in motor torque, reduction of these fluctuations willimprove circuitry performance. More specifically, the second harmonic ofmotor noise is created by the differences in full and half-step torque,and the higher order harmonics are created by deviation from asinusoidal drive wave form and from the chopping action of chips 1702and 1704.

Referring to the node 1726 at the VR pins of chips 1702 and 1704, thevoltage at this point has a relative signal level of 100% when only onephase of chip 1702, 1704 is enabled, and a reduced signal level (e.g.52%) when both phases are enabled. The exact reduction of signal leveldepends upon empirical data relating to drive currents and output torquefor a particular motor 100. This produces a torque when both phases areenabled which is generally the same as the torque produced when a singlephase is enabled. By way of specific example, resistors 1720 and 1722are 620 ohms, resistor 1724 is 560 ohms, and resistor 1712 is 300milliohms.

The enable pins I0 and I1, in cooperation with the signal level at theVR pin, produce levels corresponding to 0 winding current (min.) and thetwo relative levels described above (100% or 52%). The absolutemagnitude of the 100% level is determined by resistor 1712 while therelative signal levels are determined by resistors 1720, 1722 and 1724.The absolute amplitude is also affected by the input resistance of theVR pin (e.g. 6000 ohms).

Pins MA and MB of each chip 1702 and 1704 are coupled to one of thewindings of stepping motor 100 via an appropriate wiring arrangementwhich may include an associated 4 pin connector 1727.

Referring to FIG. 18A, power supply 1512 is a conventional power supplyincluding appropriate rectification, filtering and switch mode DC-to--DCconversion circuitry (1802, 1804 and 1806) to provide ±5 volts DC fromeither 24 VAC or 24 VDC.

Referring to FIG. 19, the main ICs of processor circuit 1514 are digitalcomputer or processor 1902, a latch 1904 and RAM 1906. Circuit 1514 alsoincludes a multiplexed address and data bus 1908 coupled between port 1of processor 1902, the input of latch 1904 and the data input of RAM1906. A first address bus 1910 is coupled between port 0 of processor1902 and the seven high address lines of RAM 1906. A second address bus1912 is connected between the output of latch 1904 and the eight lowaddress lines of RAM 1906. Buses 1908 and 1912 are 8-bit buses and bus1910 is a 7-bit bus. In operation, the data from port 1 is both addressdata and data for storage in RAM 1906 which is multiplexed and bufferedwith latch 1904 such that the combination of ports 0 and 1 providesaddressing for 32K bytes of memory and data transfer with 1 byte words.The read/write signal from pin R/W is decoded into discrete read andwrite signals by invertor 1905, where the R/W line is connected to pinWE of RAM 1906 and invertor 1905 is connected between the R/W line andpin QE of RAM 1906. By way of example, processor 1902 may be a Z8microprocessor manufactured by Zilog Corp., latch 1904 may be a CMOSlatch, and RAM 1906 may be a static RAM.

The +5 v pin of processor 1902 is connected to the 5 v supply 1812. TheXTAL1, XTAL2 and GRND pins of processor 1902 are coupled to ground and 5v supply 1812 with capacitors 1914, 1916, 1918, an EMI filter 1920, anda crystal 1922 as shown to clock processor 1902 at 14.7456 MHz.

Processor circuit 1514 includes a watchdog circuit having a capacitor1924 coupled between port 2, line 7, and the cathode of a diode 1926having its anode coupled to the reset line by the parallel arrangementof a resistor 1928 and an invertor 1930. The anode and cathode of diode1926 are also coupled to 5 v supply 1812 by a capacitor 1932 and diode1934, respectively. Components 1928-1932 form a relaxation oscillatorfor resetting processor 1902. Components 1924, 1926 and 1934, inconjunction with processor 1902, operate as a charge pump to prevent therelaxation oscillator from resetting processor 1902. Port 2, line 7 ispulsed high at a rate of at least 40 Hz for at least a duration of 2.5microseconds to drive the charge pump.

Referring to FIG. 18B, battery backup circuit 1513 is connected to theCE line and V+ line of RAM 1906. Circuit 1513 is connected between 5 vsupply 1812 and ground, where line CE is connected to the collector ofan NPN transistor 1824. Line V+ is connected to the collector oftransistor 1824 by resistor 1826 and the collector of an NPN transistor1828. The emitter of transistor 1824 is connected to the /DS line ofprocessor 1902 and the base is connected to the collector of an NPNtransistor 1808 by a resistor 1810. The bases of transistors 1828 and1808 are connected to the emitter of a PNP transistor 1812 by resistors1814 and 1816, respectively. The collector of transistor 1812 isconnected to ground, where a 3 volt lithium battery 1818 is connectedbetween ground and the base of transistor 812. The base of transistor1812 is connected to the anode of a diode 1820 having its cathodeconnected to the V+ line of RAM 1706. The V+ line is also connected toground by a capacitor 1822.

Circuit 1513 provides power to RAM 1906 and disables the chip enablesignal (CE) when the voltage of the main 5 v logic supply is notsufficiently high (between 3 and 5 volts). In operation, when the logicsupply is sufficiently high, the emitter-base junctions of transistors1828 and 1808 are forward biased with conduction current limited byresistors 1814 and 1816 causing a small current to flow through theforward biased emitter-base junction of transistor 1812 (e.g. less than10 microamps). The remainder of the emitter current flows through thecollector of transistor 1812 to ground. When this occurs, the collectorof transistor 1828 provides substantially a 5 v output to the V+ pin ofRAM 1906, while reverse bias diode 1820 disconnects battery 1818.Capacitor 1822 stabilizes the voltage from transistor 1828.

With transistor 1808 conducting, current flows to the base of transistor1824, as limited by resistor 1810, and a low signal at DS, if present,is coupled to the collector of transistor 1824. If DS is high, nocurrent flows through the collector of transistor 1824 and the CE pin ispulled high by resistor 1826. Likewise, if there is insufficient voltageto forward bias transistors 1828, 1808 and 1812, the voltage at V+ onRAM 1906 falls until diode 1820 becomes forward biased and current issupplied by battery 1818. With transistor 1808 non-conducting, a lowsignal at pin DS (emitter of transistor 1824) is not capable of makingtransistor 1824 conduct so that the CE pin connected to the collector oftransistor 1824 is pulled high by resistor 1826, thereby disabling RAM1906 when the logic supply voltage is insufficiently high.

Referring to FIG. 20, interface circuit 1518 is coupled to ports 2 and3. More specifically, circuit 1118 is coupled to the MODE0 and MODE1pins of port 2, the TD and HSO pins of port 3, and the RD and HSI pinsof port 3. Circuit 1518 is also coupled to a pair of 8 pin DINconnectors 1526 and 1528 which are arranged in parallel. Connectors 1526and 1528 provide a communication link between check reader 10 and otherdevices.

Circuit 1518 includes 5 external interface terminals, R1, R0, SGND, T0and T1, which are external device connections connected to the 8 pin DINconnector. The external interface terminals are all connected to abuffering and level shifting circuit 2002. Circuit 2002 presents a highimpedance to the external interface signals, e.g. greater than 20 kohms, and attenuates and shifts the input signal levels since the inputcommon mode range exceeds the supply voltage of circuit 1518. Theoutputs of circuit 2002 are applied to 6 comparators 2004, 2006, 2008,2010, 2012 and 2014. More specifically, the inverting and non-invertinginputs of comparator 2004 are connected to interface terminals T0 andT1, respectively; the inverting and non-inverting inputs of comparator2006 are connected to interface terminals R0 and R1, respectively; theinverting and non-inverting inputs of comparator 2008 are connected tointerface terminal TO and 2.5 v, respectively; the inverting andnon-inverting inputs of comparator 2010 are connected to interfaceterminal T1 and 2.5 v, respectively; the inverting and non-invertinginputs of comparator 2012 are connected to SGND and interface terminalR0, respectively; and the inverting and non-inverting inputs ofcomparator 2014 are connected to SGND and interface terminal R1,respectively.

The outputs of comparators 2004, 2006, 2008 and 2012 are connected to ademultiplexer 2016 which selects one signal from one of comparators2004, 2006, 2008 and 2012, and applies the signal to digital interfaceterminal RD. The selection of the signal depends upon the signal appliedto a two conductor bus 2018 which is coupled to the interface selectionterminals MODE0 and MODE1 of processor 1902 (port 2, lines 5 and 6,respectively). The outputs of comparators 2010 and 2014 are connected toa demultiplexer 2020 which selects one signal from one of comparators2010 and 2014, and applies the signal to digital interface terminal HSIof processor 1902 (port 3 line 3). The selection of the signal alsodepends upon the signal applied to bus 2018 which is coupled to theterminals MODE0 and MODE1.

Bus 2018 is also connected to a logic circuit 2022 having digitalinterface terminals coupled to the TD and HSO lines of processor 1902.Circuit 2022 is also coupled to a pair of 4 conductor buses 2024 and2026 which are connected to output switches 2028 and 2030, respectively.Each switch 2028 and 2030 has a single output coupled to terminals T1and T0 of circuit 2002, respectively. The outputs of switches 2028 and2030 depend upon the status of buses 2024 and 2026 to provide thepossibility of 4 unique analog drive levels at each switch 2028 and2030.

Interface circuit 1518 provides an interface chip which allows theselection of a plurality of communication interface standards.Presently, circuit 1118 allows selective use of RS 485, RS 423, RS 422and TTL communication standards. The signals on the external interfacepins (TI, T0, SGND, R0, R1) depend upon the selected communicationstandard and are summarized in Table B below.

                  TABLE B                                                         ______________________________________                                        Descripiton of Output Signals                                                 Signal   RS-423    TTL       RS-422 RS-485                                    ______________________________________                                        T1       DTR       AUX       Tx-    Rx/Tx-                                    T0       TD        DATA      TxT    Rx/Tx+                                    SGND     SGND                                                                 R0       RD                  Rx+                                              R1       DSR                 Rx-                                              ______________________________________                                    

Where DTR is DATA TERMINAL READY (output) ; TD is TRANSMITTED DATA(output) ; SGND is SIGNAL GROUND (input) ; RD is RECEIVED DATA (input);DSR is DATA SET READY (input); AUX is TTL HANDSHAKE (open collector);DATA is NON-INVERTED DATA (open collector); Tx+, Tx- are RS-422 TRANSMITPAIR; Rx+, Rx- are RS-422 RECEIVE PAIR; and Rx/Tx+, Rx/Tx- are RS485BIDIRECTIONAL PAIR.

The communication standard depends upon the status of bus 2018, i.e. thestatus of MODE0 and MODE1 pins as summarized in Table C below.

                                      TABLE C                                     __________________________________________________________________________                                RD     HSI                                                                    Comparator                                                                           Comparator                                 MODE0                                                                              MODE1                                                                              TD HSO                                                                              T0    T1    Selected                                                                             Selected                                   __________________________________________________________________________    RS-423                                                                        0    0    0  0  +V    +V    2012   2014                                       0    0    0  1  +V    -V    2012   2014                                       0    0    1  0  -V    +V    2012   2014                                       0    0    1  1  -V    -V    2012   2014                                       TTL                                                                           0    1    0  0  GND   GND   2008   2010                                       0    1    0  1  GND   PULLUP                                                                              2008   2010                                       0    1    1  0  PULLUP                                                                              GND   2008   2010                                       0    1    1  1  PULLUP                                                                              PULLUP                                                                              2008   2010                                       RS-422                                                                        1    0    0  0  GND   +V    2006   +V                                         1    0    0  1  N/C   N/D   2006   +V                                         1    0    1  0  +V    GND   2006   +V                                         1    0    1  1  N/C   N/C   2006   +V                                         RS-485                                                                        1    1    0  0  GND   +V    2004   +V                                         1    1    0  1  N/C   N/C   2004   +V                                         1    1    1  0  +V    GND   2004   +V                                         1    1    1  1  N/C   N/C   2004   °V                                  __________________________________________________________________________

Referring to Table C above, the analog drive levels of externalinterface pins T0 and T1 are summarized in conjunction with the statusesfor interface selection pins MODE0 and MODE1, and digital interface pinsTD and HSO. The T0 and T1 pins may have 5 drive levels including +V, -V,GND, PULLUP, and NC. For example, in RS-423 communication if TD and HSOare both low, the drive levels at T0 and T1 are V+ and V+, respectively.

Presently, there is no single chip or simple combination of chips whichallow a single device to interface interchangeably with multipleinterface standards such as RS-232 (RS-423), RS-485, RS-422 and TTL. Inthe preferred embodiment, circuit 1118 will be fabricated on a singlechip. The single chip will be an integrated circuit which allowsCMOS/TTL levels to be converted to those required for theabove-referenced interface standards. This single chip configuration isimportant where cost constraints are required and space limitations arecritical. It is contemplated that a single chip having the disclosedcomponents will be over 10 times smaller than the same circuitfabricated with discrete components on a circuit board. Additionally,the cost may be reduced by a factor in the range of 10-to-1.

Referring to FIG. 21, display circuit 1516 includes LED display 134, apair of shift registers 2102, 2104, a plurality of resistors 2106 and adata bus 2108. Registers 2102 and 2104 are coupled in parallel to bus2108 by resistor 2106. Bus 2108 is coupled to the segments of display134, and the status of registers 2102 and 2104 determines which of the16 segments are illuminated. Pins A and B of register 2102 are coupledto port 2, line 0 of microprocessor 1902, pins CLK of both registers arecoupled to port 2, line 4, and pins CLR of both registers are coupled toport 2, line 4. Pins A and B of register 2104 are coupled to pin QH ofregister 2102, and 16 bits of data are clocked into registers QA-QH ofregisters 2102 and 2104 from port 2, line 0. This arrangement allows theapplication of display data to display 134 using serial data transferfrom microprocessor 1902.

By way of example, registers 2102 and 2104 may be 74HC164s and display134 may be a LTP-537G.

The programming of processor circuit 1514 will now be described inreference to FIG. 22. In general, the programming for circuit 1514 isdesigned to configure microprocessor 1902 to provide control circuitsfor performing the various control functions of check reader 10. Whilethe programming is set up to provide a number of control circuits withinprocessor 1902, the most relevant control circuits are shaping filtercircuit 2202, buffer reconfiguration circuit 2206, sample countercircuit 2214, accumulator circuit 2212, comb filter circuit 2216,recognition circuit 2218, and protocol conversion circuit 2222. Thesource code for the relevant programming is included in Appendix Abelow. Before describing these circuits in detail, the sample timing andmotor control will first be discussed.

Processor 1902 simultaneously applies the appropriate signals to A/Dcircuit 1504 and motor drive circuit 1510 such that motor 100 is steppedone increment at the time the sample from A/D 1504 is applied toprocessing circuit 1514. Each sample from A/D 1514 is applied byprocessor 1902 to a circular buffer 2200 which is set up in RAM 1906with a memory size sufficient to store 14 samples.

Processor 1902 is programmed to provide a shaping filter circuit 2203which compensates for the frequency response of the combination of head110, amplifier and prefilter circuit 1502, and A/D circuit 1504. Ingeneral, filtering circuit 2202 provides a time-domain convolutionalfilter between its input and output. In operation, the filter operateson data buffer 2200. Buffer 2200 is a 14 byte shift register where eachdata point is advanced one position for each new data point, from A/D1504, with the oldest being discarded. RAM 1906 also includes 14 bytesof information (configuration data) corresponding to the characteristicsof the frequency response of head 112, amplifier/preamplifier circuit1502, and A/D 1504 which is written into memory during set-up. Each timea data point is written into buffer 2200, filter circuit 2202 performsits filtering process using the 14 samples to produce a data point whichis written into a circular buffer 2204.

In particular, shaping filter circuit 2202 operates for each samplewritten into buffer 2200 from A/D 1504. For each operation, theconfiguration data is multiplied with the data in buffer 2200, summedand then scaled. In particular, each of the 14 values of configurationdata K=0 to K=13 corresponds to one of the 14 memory locations in buffer2200. Each configuration data value is always multiplied with the datapoint in the associated memory location of buffer 2200. Thus, to carryout the filtering process, each configuration value is multiplied by thedata in the associated memory location of buffer 2200, the products aresummed, and the sum is divided by a scaling factor such as 14.Subsequently, the result of this filtering process is written intocircular buffer 2204.

In addition to selecting the configuration data values based upon thefrequency response of head 110, circuit 1502 and A/D 1504, these valuesmay also be based upon the type of character recognition reader 10 isperforming, e.g. E-13 or CMC-7 character recognition.

To accomplish all of the multiplication steps required during the timeperiod between the application of each data point from A/D 1504 tocircular buffer 2200, the following modified multiply process is used inplace of a typical sequential multiplication process. In general, theprocess reduces the number of operations (shifts) which would berequired with a typical multiply process. For purposes of thedescription of the procedure, the samples in buffer 2200 will bereferred to as S0 to S13 with S0 being the last in and S13 being thefirst in. The configuration data will be referred to as K0 to K13 wherethe multiplication process multiplies S0 to S13 with K0 to K13,respectively.

To carry out the process, data K0 to K13 are stored as factors of powersof 2. For example, a coefficient of 5 is 1+4, a coefficient of 4 is 4, acoefficient of 3 is 1+2, a coefficient of 6 is 2+4, etc. To perform themultiply process, the sample data S0 to S13 are multiplied by placevalues of coefficients K0 to K13 having the highest magnitude, (e.g. 4)and are multiplied by two. Subsequently, the same step is performed forthe sample data (S0 to S13) for the next highest place value (e.g. 2)and so on until this step is performed for all place values. Inherently,the products of the steps are added to provide the overall products forthe multiply process.

The following is an example of the process with numbers. Assume allsamples S0 to S13 are various values from A-D 1504, with K0 to K13 asfollows:

    ______________________________________                                        VALUE        PLACE VALUES                                                     ______________________________________                                        K0 = 1       1                                                                K1 = 5       4 + 1                                                            K2 = 6       4 + 2                                                            K3 = 4       4                                                                K4 = 2       2                                                                K5 = 3       2 + 1                                                            K6 = 5       4 + 1                                                            K7 = 7       4 + 2 + 1                                                        K8 = 6       4 + 2                                                            K9 = 4       4                                                                K10 = 1      1                                                                K11 = 1      1                                                                K12 = 1      1                                                                K13 = 1      1                                                                ______________________________________                                    

The first step would be to add S0-S3 and S6-S9, then multiply by 2. Thesecond step would be to add S2, S4, S5, S7 and S8, and again multiply by2. The third step would be to add S0, S1, S5-S7 and S11-S13. Finally,the sum would be divided by 14.

As discussed above, the operation of motor drive circuit 1510 and theinitiation of sampling at A/D 1504 is provided by a signal from phototransistor 132 which is applied to processing circuit 1514. The signalfrom photo transistor 132 is in the form of a pulse and is produced whenthe edge of the document passes over sensor port 38. Thus, the passingof the left edge 170 of check over sensor port 38 will cause processingcircuit to initiate the application of signals to motor drive circuit1510 and sampling signals to A/D 1504, and the passage of the right-handedge 160 of check 158 past sensor port 38 will discontinue theapplication of stepping signals to motor drive 1510 and sampling signalsto A/D 1504. There is an exception to this sequence in that the passageof an edge of a check over sensor port 38 will not initiate the readingprocess unless the interrupt associated photo transistor 132 is enabled.This permits check reader 10 to complete the character recognitionprocess for a single check before a second check is passed through checkreader 10.

Since photo transistor 132 is located to sense the edge of a checkpassing over sensor port 38 and sensor port 38 is located before drivewheel 92 along the path of movement of a check 158 through reader 10,the passage of a check past port 38 will cause processing circuit 1514to initiate and continue the operation of motor 100 and the sampling ofsignals from head 110 via motor drive 1510 and A/D 1504, respectively,irregardless of whether or not a check has actually been engaged betweendrive wheel 92 and the top surface of read head 110. Accordingly, sincebuffer 2204 is a circular buffer and does not have unlimited size (e.g.8KB), the samples taken from A/D 1504 are stored sequentially andwritten over the samples which were first to be stored into the buffer.Thus, samples will be stored in buffers 2200 and 2204, and motor 100will be stepped (driven) until right-hand edge 160 of check 158 issensed by photo transistor 132. As a result, at the end of a read cycle,buffer 2204 will include data which is representative of the MICRinformation which is arranged in buffer 2204 in such a way which doesnot correspond to right-to-left reading of check 158.

After completion of a read cycle, buffer reconfiguration circuit 2206 ofprocessor 1902 rearranges the data in circular buffer 2204 to put it inorder as if the check was read from right to left. Circuit 2206 isrequired since reader 10 reads the MICR information from a check 158from the left to the right, whereas typical readers read MICRinformation from the right to the left. Accordingly, for programprocessor 1902 to have a recognition circuit 2218 capable of usinggenerally standard recognition methods, it is most efficient torearrange the data in circular buffer 2204. Rearrangement places thedata in an order which is sequential and begins from the datarepresentative of the rightmost MICR information and ending with thedata which is representative of the leftmost MICR information.

Circuit 2206 utilizes a pointer located at the memory location of thelast data written into buffer 2204. Circuit 2206 looks at the data aboveand below the pointer and reconfigures the data above the pointer. Afterreconfiguration the first is last and the last is first, with allintermediate data correspondingly interchanged. The data below thepointer is reconfigured to make the last first and the first last, withthe intervening data correspondingly interchanged. For example, ifbuffer 2204 were an 8 element buffer (n=0 to n-7), where element n=5(left most) was the first element written in and element n=4 (rightmost) was the last element written in, with the pointer at element n=4,circuit 2206 would reconfigure the data in the following order: N4, N3,N2, N1, N0, N7, N6, N5. As can be seen, this reconfiguration places thedata in sequential order from the beginning of the read cycle (elementN5) to the end of the read cycle (element N4) in order as if read fromright to left.

Processor 1902 also operates as a sample counter 2214. Sample counter2214 keeps track of the number of samples which are written into buffer2204 and is important in the situation where buffer 2204 is notcompletely filled during a read cycle (the time between motor run startand sample start and motor run stop and sample stop). For example,buffer 2204 has enough memory to store all of the samples taken whilereading a check which is 8 inches long. As discussed above by way ofexample, check 158 was described as a personal check which is only 6inches long. Accordingly, where a personal check is fed to the feeder,without hesitation at port 38, buffer 2200 will not be completely filledwith sample data and the count at sample counter 2214 will be importantto determine what portion of the data in buffer 2200 is representativeof the MICR information on the check which was read. Thus, where thesample count at 2214 is less than the capacity of buffer 2204,reconfiguration circuit 2206 accounts for the difference beforereconfiguring.

As the data is written into circular buffer 2204, it is also writteninto a third buffer 2210 via an accumulator circuit 2212. Accumulatorcircuit 2212 operates to sum every n=1 to n=128 data point written intobuffer 2204, and write the sums into the 128 locations of buffer 2210.At the end of a read cycle, each sum is divided by the number of sampleswhich were accumulated for the particular sum.

Buffer 2210 is sized based upon the sampling frequency of A/D 1504, andthe number of samples corresponding to one cycle of a frequency whichshould be filtered from the data stored in circular buffer 2204. In thepresent embodiment, circular buffer 2210 stores 128 data points, whichcorresponds to one cycle of a 60 Hz (power line) signal which isfiltered from the data stored in circular buffer 2204. In particular,the size of buffer 2210 corresponds to 16 steps per cycles of motordrive signal (30° rotation) of the motor, and 8 rotations of the motorfor each cycle of the 60 Hz frequency (8*16=128 data points).

Subsequent to reconfiguring the order of the data in buffer 2204, combfilter 2216 filters the data in buffer 2204 based upon the data inbuffer 2210. More specifically, filter circuit 2216 reads the first setof 128 values in buffer 2204, subtracts the corresponding 128 datapoints in buffer 2210, and rewrites the differences back into theappropriate locations in buffer 2204. Filter 2216 repeats this processfor every set of 128 data points in buffer 2204 until all of the datapoints have been filtered.

The use of a 128 point buffer for buffer 2210 is based upon the filter(60 Hz) which is being filtered from the data in buffer 2204 and thenumber of samples written from A/D 1504 to buffer 2204 during one cycleof the filtered frequency. However, depending upon the application, thefrequency of the signal desired to be filtered from the data in buffer2204 may change, depending upon the application. Thus, the size ofbuffer 2210 would be modified accordingly. However, to maintaincorrespondence between the N data points in buffer 2210 and the sets ofN data points in buffer 2204, the size of buffer 2204 must be an integermultiple of the size of buffer 2210. Also buffer 2210 must be an integermultiple of the number of samples corresponding to a single cycle of themotor drive signal (30° rotation).

Processor 1902 is programmed to provide a recognition circuit 2218 whichrecognizes a particular magnetic character set being read from check158. Circuit 2218 is provided by programming using conventionalrecognition procedures, and operates to read the data from buffer 2204,reconfigure the data according to the procedures for the particularcharacter recognition, and rewrite the data into buffer 2220. The datafrom buffer 2220 is output after being reconfigured in a conventionalmanner by protocol circuit 2222 to convert the data into a form havingthe appropriate protocol for the desired communication. The data fromprotocol circuit 2222 is applied to the UART 2224 of microprocessor 1902and output at port 3, lines 0 and 7.

It will be understood that the foregoing description is of preferredexemplary embodiments of the present invention, and the invention andinventive modifications thereof are not limited to the details shown anddescribed. For example, some of the inventive features are directed tohand-fed check readers (i.e. check readers where an operator applies thechecks to the reader, rather than having a feed device batch feed checksto the reader at high speeds) and other features are directed moregenerally to devices which interact (i.e. read or write) with themagnetic information of a document. Additionally, the details of thedocument drive mechanism, housing, and software/microprocessorcombination may be modified to tailor the check reader to a particularsituation. For example, the system may be modified to read or checkmagnetic information from paper currency or magnetically encoded cardssuch as credit cards. These and other modifications may be made withoutdeparting from the scope of the invention as expressed in the appendedclaims. ##SPC1##

What is claimed is:
 1. A device for interacting with magneticinformation of a moving surface, comprising:a circuit board fabricatedfrom a material, and including a support portion and a first supportmember, where the support portion and the first support member arefabricated from the material such that the support portion is suspendedrelative to the circuit board to permit resilient deflection of thesupport portion relative to the circuit board; a transducer configuredto interact with the magnetic information of the moving surface, wherethe transducer is mounted to the support portion; an amplifier circuitlocated upon the circuit board; and an interface circuit electricallyconnected between the transducer and the amplifier circuit, and locatedupon the circuit board.
 2. The device of claim 1, where the transduceris a magnetic read head including a top surface having a magneticsensor.
 3. The device of claim 1, further comprising a housing whichincludes a housing surface for supporting the moving surface, where thecircuit board is mounted to the housing such that the transducer is incontact with the moving surface.
 4. The device of claim 2, furthercomprising a housing which includes a housing surface for supporting themoving surface, where the circuit board is mounted to the housing suchthat the top surface of the magnetic read head is in contact with themoving surface and the magnetic information on the moving surface ismagnetically encoded.
 5. The device of claim 4, further comprising asecond support member fabricated from the material and extending betweenthe circuit board and the support portion.
 6. The device of claim 1,wherein the transducer is a magnetic write head.
 7. A device for readingmagnetically encoded information from a document, comprising:asubstantially planar circuit board fabricated from a material, thecircuit board including a head support portion and at least one supportmember, where the head support portion and the at least one supportmember are fabricated from the material such that the head supportportion is suspended relative to the circuit board to permit elasticdeflection of the head support portion relative to the board; a readhead configured to read the magnetically encoded information from thedocument, where the read head is mounted to the head support portion;and a circuit electrically coupled to the read head to produce signalsrepresentative of the magnetically encoded information, where thecircuit is located upon the circuit board.
 8. The device of claim 7,where the circuit is printed on the circuit board.
 9. The device ofclaim 7, where the circuit board is disposed along a plane, and the headsupport portion is suspended along the plane.
 10. The device of claim 7,further comprising a housing including a document support surface havinga first opening at which magnetically encoded information may be read,where the circuit board is supported by the housing such that the readhead is located at the first opening.
 11. The device of claim 7, furthercomprising a second support member fabricated from the material andextending between the circuit board and the head support portion. 12.The device of claim 11, where the head support portion is rectangular,and the at least one support member and the second support member areL-shaped members.
 13. The device of claim 7, further comprising adigital computer mounted on the circuit board and connected to thecircuit.
 14. The device of claim 7, wherein the circuit is an amplifiercircuit.
 15. A device for reading magnetically encoded information froma document, comprising:a housing including a document support surfacehaving a first port at which magnetically encoded information may beread; a circuit board including a head support portion and at least onesupport member, where the head support portion and support member arefabricated from the material of the circuit board such that the headsupport portion is suspended relative to the circuit board by the atleast one support member to permit elastic deflection of the headsupport portion relative to the circuit board; a read head configured toread the magnetically encoded information from the document, where theread head is mounted to the head support portion; and a circuitelectrically coupled to the read head to produce signals representativeof the magnetically encoded information, where the circuit is locatedupon the circuit board and the circuit board is supported by the housingsuch that the read head is located at the first port.
 16. The device ofclaim 15, further comprising an illuminating device and an opticalsensor both electrically coupled to the circuit, where the documentsupport surface includes an optical sensing site at which an edge of thedocument may be sensed, the illuminating device and optical sensor beingmounted to the circuit board such that they are located proximate theoptical sensing site.
 17. The device of claim 16, wherein the read headcomprises a top surface including a magnetic sensor, wherein the readhead is mounted to the head support portion and the circuit board ismounted to the housing such that the top surface lays in substantially asame plane as the document support surface.
 18. The device of claim 17,further comprising a document drive wheel including a centrally disposedrotational axis and a perimeter surface, and a rotating mechanism, wherethe document drive wheel is mounted on the rotating mechanism and therotating mechanism is supported by the housing such that the perimeterof the document drive wheel engages the top surface of the read head todeflect the head support portion.
 19. The device of claim 18, whereinthe rotating mechanism comprises:a shaft upon which the document drivewheel is mounted; a first gear mounted to the shaft; a bearing having abearing surface disposed about the shaft to rotatably support the shaftabout the rotational axis, the bearing being mounted to the housing; anelectric motor including a motor shaft; and a second gear mounted to themotor shaft, where the motor is mounted to the housing such that thefirst and second gears mesh.
 20. The device of claim 19, wherein theelectric motor is a 2-pole stepping motor electrically coupled to thecircuit, and the circuit includes circuitry configured to control therotation of the electric motor.
 21. A check reader for readingmagnetically encoded information from a check, comprising:a housinghaving a generally planar check support surface, bounded on one side bya generally straight rail, where the housing defines a first openingextending through the housing adjacent to the rail; a circuit boardincluding at least one groove defining a spring member within thecircuit board bounded by the groove, where the spring member includes ahead support portion and a first support member extending between thecircuit board and the head support portion such that the head supportportion is suspended relative to the circuit board by the first supportmember to permit elastic deflection of the head support portion relativeto the circuit board; a read head configured to read the magneticallyencoded information from the check, where the read head is mounted tothe head support portion; and a circuit electronically coupled to theread head to produce signals representative of the magnetically encodedinformation, where the circuit is located upon the circuit board and thecircuit board is supported generally parallel to the check supportsurface and within the housing such that the read head extends into thefirst opening.
 22. The reader of claim 21, further comprising a digitalcomputer mounted to the circuit board and coupled to the circuit, wherethe circuit applies the signals representative of the information to thedigital computer.
 23. The reader of claim 21, the circuit including asignal amplifying circuit.
 24. The reader of claim 21, furthercomprising an illuminating device and an optical sensor bothelectrically coupled to the circuit, where the check support surfaceincludes an optical sensing site at which an edge of the document may besensed, the illuminating device and optical sensor being mounted to thecircuit board such that they are located proximate the optical sensingsite.
 25. The reader of claim 21, the read head comprising a top surfaceincluding a magnetic sensor, wherein the read head is mounted to thehead support portion and the circuit board is mounted to the housingsuch that the top surface lays in substantially a same plane as thedocument support surface.
 26. The reader of claim 21, further comprisinga check drive wheel including a centrally disposed rotational axis and aperimeter surface, and a rotating mechanism, where the check drive wheelis mounted on the rotating mechanism and the rotating mechanism issupported by the housing such that the perimeter of the wheel engagesthe top surface of the read head.
 27. The reader of claim 26, whereinthe rotating mechanism comprises:a shaft upon which the check drivewheel is mounted; a first gear mounted to the shaft; a bearing having abearing surface disposed about the shaft to rotatably support the shaftabout the rotational axis, the bearing being mounted to the housing; anelectric motor including a motor shaft; and a second gear mounted to themotor shaft, where the motor is mounted to the housing such that thefirst and second gears mesh.
 28. The reader of claim 27, wherein theelectric motor is a stepping motor electrically coupled to the circuit.29. The reader of claim 26, further comprising a second support memberextending between the circuit board and the head support portion.
 30. Acheck reader for reading magnetically encoded information from a check,comprising:a housing having a generally planar check support surfacebounded on one side by a generally straight surface extending upwardlyand substantially perpendicular to the check support surface, where thehousing defines a first opening extending through the housing adjacentto the straight surface; a circuit board including at least two groovesdefining a spring member including a head support portion bounded by thegrooves and a pair of support members extending between the board andthe head support portion such that the head support portion is suspendedrelative to the circuit board by the pair of support members to permitelastic deflection of the head support portion relative to the board; amagnetic read head mounted to the head support portion; and a circuitelectrically coupled to the read head and located upon the circuitboard, where the circuit board is supported generally parallel to thehead support surface within the housing such that the read head extendsinto the first opening.
 31. The reader of claim 30, wherein the supportmembers are generally L-shaped.
 32. The reader of claim 30, furthercomprising a digital computer mounted to the circuit board and coupledto the circuit.
 33. The reader of claim 30, wherein the circuit includesan amplifier.
 34. The reader of claim 32, further comprising anilluminating device and an optical sensor both electrically coupled tothe circuit, where the support surface includes an optical sensing siteat which an edge of the check may be sensed, the illuminating device andoptical sensor being mounted to the circuit board such that they arelocated proximate the optical sensing site.
 35. The reader of claim 34,the read head comprising a top surface, wherein the read head is mountedto the head support portion and the circuit board is mounted to thehousing such that the top surface lays in substantially a same plane asthe document support surface.
 36. The reader of claim 31, furthercomprising a check drive wheel including a centrally disposed rotationalaxis and a perimeter surface, and a rotating mechanism, where the checkdrive wheel is mounted on the rotating mechanism and the rotatingmechanism is supported by the housing such that the perimeter of thecheck drive wheel engages the top surface of the read head.
 37. Thereader of claim 36, wherein the rotating mechanism comprises:a shaftupon which the check drive wheel is mounted; a first gear mounted to theshaft; a bearing having a bearing surface disposed about the shaft torotatably support the shaft about the rotational axis, the bearing beingmounted to the housing; an electric motor including a motor shaft; and asecond gear mounted to the motor shaft, where the electric motor ismounted to the housing such that the first and second gears mesh. 38.The reader of claim 37, wherein the electric motor is a stepping motorelectrically coupled to the circuit.